Skid steer loader machines are manufactured to provide a compact work machine which is maneuverable and durable in various applications. Some skid steer loader machine frames are designed to isolate the forces incurred during operation while other skid steer loader machine frames are designed to facilitate efficient assembly of various components. There is always a continuing need for improved methods of manufacturing and assembling skid steer loader machines due to high demand and competitive forces. Such improvements should include decreased manufacturing and assembly time and costs coupled with increased durability of the skid steer loader machines.
Some skid steer loader machines use a loader body or lower frame assembly in conjunction with a subframe or upper frame assembly to define a main frame assembly for the loader machine. The upper frame assembly typically has an upright fabrication and is mounted to the lower frame assembly so that the upright fabrication partially encloses the engine.
A design disclosed in U.S. Pat. No. 3,895,728 issued to John P. Heggen on Jul. 22, 1975 is an example of a assembly of a subframe and loader body wherein the subframe includes a pair of laterally spaced, longitudinally extending side beams mounted to bosses positioned over the stub axles projecting from opposite sides of the loader body. The arrangement substantially isolates material handling forces from the loader body and facilitates location of the drive components in a single body compartment. A design disclosed in U.S. Pat. No. 4,955,455 issued to Larry E. Albright et al. on Sep. 11, 1990 utilizes a method of assembling a skid steer loader which mounts an engine and hydraulic pump to an engine mount platform welded at the back end of the lower frame assembly. The engine mount platform is designed for increased accessibility so that the engine and hydraulic pump can be easily mounted together resulting in decreased assembly time. The engine mount platform accessibility is achieved by utilization of the engine mounting platform as part of the connection for the upper frame assembly with the lower frame assembly, including vertical bolts therebetween. Horizontal bolts are used to further connect the upper frame assembly to a pair of side rails of the lower frame assembly which extend partially along the length thereof. Both designs, however, do not provide for a continuous and consistent connection along the entire length of the lower frame assembly thereby producing an unequal distribution of loading therealong. The use of horizontal and vertical connections between the upper and lower frame assemblies causes variations in the loading stresses on the assembled main frame assembly due to differences in the bolting pattern. Additionally, the use of the engine mount platform as part of the connection with the upper frame assembly may increase the risk of engine vibration being transferred directly into the upper frame assembly.
The present invention is directed to overcoming the problems as set forth above.